/*
 * Copyright (C) 2015-2018 Alibaba Group Holding Limited
 */


#ifndef NGHTTP2_OUTBOUND_ITEM_H
#define NGHTTP2_OUTBOUND_ITEM_H

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /* HAVE_CONFIG_H */

#include <nghttp2/nghttp2.h>
#include "nghttp2_frame.h"
#include "nghttp2_mem.h"

/* struct used for HEADERS and PUSH_PROMISE frame */
typedef struct {
  nghttp2_data_provider data_prd;
  void *stream_user_data;
  /* error code when request HEADERS is canceled by RST_STREAM while
     it is in queue. */
  uint32_t error_code;
  /* nonzero if request HEADERS is canceled.  The error code is stored
     in |error_code|. */
  uint8_t canceled;
} nghttp2_headers_aux_data;

/* struct used for DATA frame */
typedef struct {
  /**
   * The data to be sent for this DATA frame.
   */
  nghttp2_data_provider data_prd;
  /**
   * The flags of DATA frame.  We use separate flags here and
   * nghttp2_data frame.  The latter contains flags actually sent to
   * peer.  This |flags| may contain NGHTTP2_FLAG_END_STREAM and only
   * when |eof| becomes nonzero, flags in nghttp2_data has
   * NGHTTP2_FLAG_END_STREAM set.
   */
  uint8_t flags;
  /**
   * The flag to indicate whether EOF was reached or not. Initially
   * |eof| is 0. It becomes 1 after all data were read.
   */
  uint8_t eof;
  /**
   * The flag to indicate that NGHTTP2_DATA_FLAG_NO_COPY is used.
   */
  uint8_t no_copy;
} nghttp2_data_aux_data;

typedef enum {
  NGHTTP2_GOAWAY_AUX_NONE = 0x0,
  /* indicates that session should be terminated after the
     transmission of this frame. */
  NGHTTP2_GOAWAY_AUX_TERM_ON_SEND = 0x1,
  /* indicates that this GOAWAY is just a notification for graceful
     shutdown.  No nghttp2_session.goaway_flags should be updated on
     the reaction to this frame. */
  NGHTTP2_GOAWAY_AUX_SHUTDOWN_NOTICE = 0x2
} nghttp2_goaway_aux_flag;

/* struct used for GOAWAY frame */
typedef struct {
  /* bitwise-OR of one or more of nghttp2_goaway_aux_flag. */
  uint8_t flags;
} nghttp2_goaway_aux_data;

/* struct used for extension frame */
typedef struct {
  /* nonzero if this extension frame is serialized by library
     function, instead of user-defined callbacks. */
  uint8_t builtin;
} nghttp2_ext_aux_data;

/* Additional data which cannot be stored in nghttp2_frame struct */
typedef union {
  nghttp2_data_aux_data data;
  nghttp2_headers_aux_data headers;
  nghttp2_goaway_aux_data goaway;
  nghttp2_ext_aux_data ext;
} nghttp2_aux_data;

struct nghttp2_outbound_item;
typedef struct nghttp2_outbound_item nghttp2_outbound_item;

struct nghttp2_outbound_item {
  nghttp2_frame frame;
  /* Storage for extension frame payload.  frame->ext.payload points
     to this structure to avoid frequent memory allocation. */
  nghttp2_ext_frame_payload ext_frame_payload;
  nghttp2_aux_data aux_data;
  /* The priority used in priority comparion.  Smaller is served
     earlier.  For PING, SETTINGS and non-DATA frames (excluding
     response HEADERS frame) have dedicated cycle value defined above.
     For DATA frame, cycle is computed by taking into account of
     effective weight and frame payload length previously sent, so
     that the amount of transmission is distributed across streams
     proportional to effective weight (inside a tree). */
  uint64_t cycle;
  nghttp2_outbound_item *qnext;
  /* nonzero if this object is queued, except for DATA or HEADERS
     which are attached to stream as item. */
  uint8_t queued;
};

/*
 * Initializes |item|.  No memory allocation is done in this function.
 * Don't call nghttp2_outbound_item_free() until frame member is
 * initialized.
 */
void nghttp2_outbound_item_init(nghttp2_outbound_item *item);

/*
 * Deallocates resource for |item|. If |item| is NULL, this function
 * does nothing.
 */
void nghttp2_outbound_item_free(nghttp2_outbound_item *item, nghttp2_mem *mem);

/*
 * queue for nghttp2_outbound_item.
 */
typedef struct {
  nghttp2_outbound_item *head, *tail;
  /* number of items in this queue. */
  size_t n;
} nghttp2_outbound_queue;

void nghttp2_outbound_queue_init(nghttp2_outbound_queue *q);

/* Pushes |item| into |q| */
void nghttp2_outbound_queue_push(nghttp2_outbound_queue *q,
                                 nghttp2_outbound_item *item);

/* Pops |item| at the top from |q|.  If |q| is empty, nothing
   happens. */
void nghttp2_outbound_queue_pop(nghttp2_outbound_queue *q);

/* Returns the top item. */
#define nghttp2_outbound_queue_top(Q) ((Q)->head)

/* Returns the size of the queue */
#define nghttp2_outbound_queue_size(Q) ((Q)->n)

#endif /* NGHTTP2_OUTBOUND_ITEM_H */
